Air separation device for large liquid amount preparation and method

The invention relates to an air separation device for large liquid amount preparation and a method. The air separation device comprises an air filter, an air compressor, a purification unit, a supercharger, a high-low-temperature supercharged turbine expander and a cryogenic separation cold box unit. Compressed air directly undergoes heat exchange and then enters a lower tower partially, and undergoes supercharging by the supercharger and then is cooled and throttled to enter the lower tower partially, air pumping is carried out in the supercharger, the air undergoes double-supercharging double-expansion of the high-low-temperature supercharged turbine expander and then enters the lower tower, the product oxygen and the product nitrogen adopt a double-pump internal compression process, andan argon-making system adopts an oxygen-enriched liquid air total-reflux form. According to the disclosed method of the air separation device for large liquid amount preparation by cryogenic separation, the step of air pumpi